[coloradan]

The word "normal" is ambiguous. If, on average, one chicken in a million has two heads, such chickens would not be normal(1) in the sense that, by far, most of them have only one head, but on the other hand it would be normal(2) if, in the future, one in a million continued to have two heads. In fact, if a billion chickens were then born, and zero of them had two heads - that would not be normal(2). Tetragametic chimerism in humans is rare and therefore not normal(1), but them being born once in a while is entirely normal(2).

[Beagle8U]

Normal is a baseline of the expected standard.

Without normal there would be no mental illness, which we know isn’t true.

You can’t cure mental illness by denying normal exists.